North Korea has apologised to bereaved families after an apartment building collapsed in Pyongyang, possibly killing hundreds, the official KCNA news agency says.

It is a rare admission of fallibility from the reclusive state, but no death toll was given.

Pyongyang's expression of "profound consolation and apology" was the first official news of the disaster, which happened in the Phyongchon district of the North Korean capital last Tuesday.

"The construction of an apartment house was not done properly and officials supervised and controlled it in an irresponsible manner," said the statement from KCNA.

The statement said the collapse of the apartment building "claimed casualties" but did not give any indication of how many had been killed or injured.

A rescue operation ended on Saturday, it said.

A South Korean official confirmed a 23-storey building collapsed in Pyongyang.

He said the building was believed to have accommodated 92 households or families, and it was common for North Koreans to move into new buildings before construction was completed.

"Hundreds are presumed to be dead, assuming that each family has an average of four members," he said.

No source for the information was provided.

The KCNA statement said North Korean authorities put emergency measures in place to rescue people from the collapsed building and to treat the injured.

It said North Korea's minister of people's security, Choe Pu Il, had "repented", admitting he had failed to supervise the project adequately, "thereby causing an unimaginable accident".

The rare apology from the North came as South Korean president Park Geun-hye's administration faces criticism for its handling of a ferry disaster that killed more than 300 people, many of them schoolchildren, last month.

North Korea launched a vitriolic attack of Ms Park in the wake of that disaster.

On Saturday night, tens of thousands people attended a candlelight vigil in Seoul for victims of the ferry disaster.

Some marched to the presidential palace demanding Ms Park resign, with police arresting 115 of the protesters.